My 3rd son has Covid-19

My 3rd son and his wife went over to her 92 yo GM's for Christmas and the Aunt was there visiting.
They had all agreed only my son and his wife and her parents would come over to see GM. Well, the Aunt had gone during the week to a Nutcracker show her grandkids were in and she didn't wear a mask, but she didn't mention it to them, while they were all there for about 4 hours.
She was sick on Sunday and Monday tested positive for Covid-19. So my son, wife and in-laws went to be tested and were told they were negative. I told my son when he called that a test at 3 days could be negative and he should stay home from work at the news station for another two days but he went to work on Tuesday as they are short of help.
On Wednesday morning, his MIL had a fever and cough, and GM was coughing, so they all went to get tested and they are all positive.
He had his friend and his gf over to visit on Tuesday as they are in town for Christmas, so now they have to be tested and then he was around people in the news station. He's so stressed as GM is 92, and his in-laws are 64.

My 4th son got it from his wife in August as she's a RN and a patient coughed in her face, but even with a mask on she got it. The patient tested positive 3 days later. She and my son were both really sick, but got through it.